While I do want them to improve our JA range, I do want to point out that they have made gearing both master and pet for acc/atk or DT easier as time goes. Sure, not at the same time, but that's why you tap a macro to switch to DT when you see a move or spell and use your Acc/Atk set otherwise. Just examples:

Acc/Atk:
Skullrender Path C x2: 10 Atk/Acc (Master), 20 Atk/Acc , 8% Haste, and 5% DA (pet) each.
Despair Helm Path C: 30 Acc and 20 Atk (Master), 20 Acc/Atk (Pet)
Valorous Mail: Acc+20, DA+2, PDT-2% (Master), Up to Acc/Atk+20~30 (augments for pet).
Emicho Haubert Path C: Acc/Atk+15, DA+3 (Master), Acc/Atk+15, DA+3, DT-3% (Pet)
Emicho Gauntlets Path D: Acc+35, STP+6, DW+5 (Master), Acc/Atk+20, STP+6 (Pet)
Despair Greaves Path C: Acc+27, DA+2 (Master), Acc+17 (Pet)
Pastoralist's Mantle: Acc+10/Atk+20 (Master), Atk+20 (Pet), Acc up to +15 and DT up to -4% (Pet Augments)

Assuming Valorous Mail is out of reach and you go with Emicho, you're looking at:
+137 Acc, +75 Atk, +5 DA, +5 DW, +6 STP (Master)
+112~127 Acc, +105 Atk, +13 DA, +6 STP, -3~7% DT, +16% Haste

And this isn't including accessories which can boost your stats or your pet's stats higher. Empath Necklace gives +10 Acc to the master, and +10 Acc/+5 Atk to the pet. Get a good Angel Ring aug from the last fight of ACP, I've got Acc+4/Pet: Acc+6 on my augments. Waist you can do Hurch'lan Sash, with Acc+15 for them master and Acc+10/Haste+5% for the pet. Earrings you'd have to consider between the two, and I'd probably do something like Cessance/Zennanori for extra master acc, or DW earrings if you don't need that extra Acc. Legs, which were not listed above, you can do Acro with a Pet: Acc aug to get 10 acc for the master and up to 25 Acc for the pet. And then there's other augs such as Pet: Pet: Haste (which, if you get 4%, caps your pet haste via gear with the stuff above).

As for a DT build, here's what I currently use:
Izizoeksi (Pet: DT-5%) / Kumbhakarna (Aug'd with Pet: PDT-4%) / X / Vanir Battery (MDB+4)
Jumalik Helm (PDT-5%) / Twilight Torque (DT-5%) / Handler's Earring (Pet: PDT-3%) / Handler's Earring +1 (Pet: PDT-4%)
Jumalik Mail (DT-8%) / Ankusa Gloves (Pet: PDT-3%) / Dark Ring (PDT-4%/MDT-4%) / Dark Ring (PDT-4%/MDT-6%)
Pastoralist's Mantle (Pet: DT-3%) / Isa Belt (Pet: DT-3%) / Taeon Pants (Pet: DT-4%) / Taeon Boots (Pet: DT-2%)

I pop this on when I see a TP move or spell coming. Gives, in terms of PDT/MDT: 26 PDT/23 MDT (Master) and 31 PDT/17 MDT (Pet). With Shell V on the master (via trust), that nearly caps MDT, or with Shell III from the scroll, you're only 6% lower. If I capped my augs and got some DT- luck on Taeon hands to switch those in (assuming a cap of -4% on all Taeon), pet defenses start looking like 33 PDT/24 MDT. With Stout Servant, that's an additional -9% DT, so we look at 42 PDT/33 MDT.

So yeah, of late they have done a lot better for creating hybridized gear for us, and we can adapt to situations with a variety of gear sets. They still need to do something like double our current JA range though.